This invention relates to novel benzofuro[3,2-c]pyrazol-3-amine derivatives, to therapeutically acceptable acid addition salts thereof, to processes for their preparation, to methods of using the derivatives, and to pharmaceutical compositions of the derivatives. These derivatives are useful for producing analgesia in a mammal without objectionable side effects of the narcotic analgesic agents. Furthermore, the derivatives produce useful analgesia at doses, which do exhibit neither antiinflammatory nor paralytic effects. In addition, some of the derivatives are useful for inhibiting convulsions, anxiety and aggression, for producing muscle relaxation and hypnosis, and for inhibiting gastric acid secretion in a mammal.
A number of benzofuro[3,2-c]pyrazole are known and described, for example, D. N. Reinhoudt and C. G. Kouwenhove, Rec. Trav. Chim. Pays-Bas, 93, 321 (1974); Le Quoc Khanh and B. Laude, C. R. Acad. Sci., Ser. C, 276, 109 (1973); W. A. Mosher et al., J. Org. Chem., 37, 2402 (1972); K. N. Wadodkar et al., Indian J. Chem., 12, 224 (1974); and W. U. Malik et al., Indian J. Chem., 9, 655 (1971). A number of benzothieno(3,2-c)pyrazol derivatives are also known, for example, W. J. Barry et al., J. Chem. Soc., 4974 (1956); S. B. Awad et al., Aust. J. Chem., 28, 601 (1975); K. E. Chippendale et al., J. Chem. Soc., Perkin Trans. I, 129 (1973); and F. Sauter et al., Monatsh. Chem., 105, 869 (1974). The compounds reported in the above references lack the substituents on the benzofuro[3,2-c]pyrazole ring system which are characteristic of the compounds of this invention. A number of 1H-benzothieno[3,2-c]pyrazol-3-amines are disclosed by H. E. Hoffman et al., U.S. Pat. No. 4,140,785, issued Feb. 20, 1979. The latter amines are readily differentiated from the compounds thereof by having a sulfur atom in the ring system and by having as their sole use chemical intermediates for preparing compounds useful in the treatment of diseases caused by rhinoviruses.